System for locking turbine blades on a turbine wheel

Abstract

A system for locking turbine blades onto a turbine wheel is disclosed in which a locking member is disposed totally radially inwardly of the turbine blade platforms, thereby enabling the platforms to define a continuous annular wall. Turbine blades are each inserted through a 'window' and circumferentially displaced in a turbine wheel groove until space remains on the circumference of the turbine wheel for three turbine blades. The locking device cooperates with the last three turbine blades to lock the blades in position on the turbine wheel. The locking device is resiliently deformable and has a central portion having a cross-sectional shape generally similar to that of the circumferential groove. Locking flanges extend in an axial direction from the center section and engage locking notches defined by circumferentially extending ribs formed on the turbine wheel on either side of the circumferential groove. Once the locking device and the final three sealing turbine blades have been installed, all of the blades and the locking device are circumferentially displaced such that the locking flanges engage the locking notches to prevent any undesired circumferential movement. The locking notches are oriented with respect to the 'window' such that, in the locked position, no single turbine blade is in alignment with the 'window'.